Conveyer roller



April 27, 1943. L. D. DONBECK ETAL 2,317,742.

GONVEYER ROLLER Filed Dec. 22, 1959' 1760676253751 [meey 0. flo/vefae 4/74 605587 4 PETE/950M,

Patented Apr. 27, 1943 U N l T E D STATES PAT-EN FF ITCE $317,742 CONVEYER ROEEER =La'rry vD. Donbeck and Robert A. Peterson, Gary, Ind.

ApplicationDecemb'er 22, 1 939,"SerialNo. 310i617 (o1. ice-37) 2G1aims.

This invention relates to conveyer rollersfsuch as are usedinsteel mills to transport various metallic objects.

In conveyer roller lines such as are used in steel mills,'it is necessary that thetransported-medi um be shielded from scratching or marring. It is also necessary'that the wear and tear onth'e conveying equipment be minimized.

It is among the objects of the resent invention to provide a, hard polished roller'havin'g high resistance towear.

Another object is the provision of a conveye'r "roller of the type described which hasnot only the foregoing characteristics, "but also those "of body 2 of the roller is made of standard-tubing of-suitable diameter and length. 'I'he hu'b plates 1 3"are circular in shap'e' and ofa diameter which is comparable to the inside diameter "ofth'ebody 2 with sufilcient clearance to facilitate easy insertion into the roller assembly. The shaft 4 is inserted through the "hub plates 3 and body 2 after these elements have been heat-treated, as will appear more fully hereinafter.

The hub plates 3 are positioned in the body 2 and electrically spot welded in place, low carbon welding rods being used. The welds bond the hub plates to the roller completely around its periphery, as shown at 5. This feature is important for it gives equal and uniform support to the roller body throughout its entire inner circumference, thereby minimizing the liability of distortion and strain in the subsequent carburizing and heat-treatment.

In Figure 1 the hub plates 3 are shown as secured fully within the body 2 of the roller; while according to Figure 3 the said hub plates extend slightly from the body 2.

After the hub plates 3 are welded in place to form an assembly, four holes 1 of suitable size (depending on the size of the roller) are layedout on the hub plates an equal distance apart and with their centers equi-distant from the geometric center of the hub plates. These holes 7 are then burned out with acetylene torch.

The holes 1 are of great importance, for they make possible free and lowered resistance to the ducea 'smoothfinish. In. addition to producing a smoothfsurfa'ce condition, this" turningroperation is necessary "for with the general run "of "tubing,

thereis atenden'cyfor its being out ofround.

After the turning iop'eration'is completedfthe roller is again supported in .lathe chuckand center' rest, "centered, and the shaftholef9. is drilled "inaeach "hub "plate. .The "roller is now readyior "theparburizing' and heat=treatm'ent.

Before proceeding with Ia description :of the "carburizing and heat-treatment, it should be stated that they "are applicable to, and the objects of the invention obtained "onyany tube '2 which-is compose-d of tubing, skelp, plate, .strip or casting, the desired structural and physical characteristics of which can onlybe secured "by carburizing andhe'at-treatment. A specific IeX- ample may compriseflcarb'on; 0:17, manganese, 0246 ,phosphorus, -0.010 sulphur, 0.027% and silicon-0.008%; but-the teachings of the invention are applicable to approximately the --foll owing range df anal ysis 'Ca'rbo'n 0.08% to 0.35% Manganese 0.35% to 0.90% Phosphorus Minimum Sulphur Do Silicon Do The carburizing compound used is solid, containing suitable carbonaceous materials, some animal matter and barium carbonate as an energizer. Barium carbonate disassociates at high temperatures and gives off carbon dioxide (CO2) gas, which combines with the carbonaceous materials to form carbon monoxide (2C0) gas, which is essential to this type of carburizing practice. After being used, the carburizing compound is spread out in such fashion as to permit maximum exposure to the atmosphere; thus enabling the barium carbonate to revitalize itself by absorption of carbon dioxide. It will be understood by those skilled in the art that any other solid carburizing compound may be used instead of that described immediatelyhereinbefore.

According further to the teachings of the invention, the roller 2 and transfer hub plates 3 are packed in the solid carburizing compound in the carburizing temperature through the A. R. 3-2-1 points (lower critical temperature) of case, a more efficient diffusion of the carbides is obtained, thereby avoiding abrupt demarcation. This is an important feature, as it minimizes the potential danger of spawling and quenching strain during the hardening treatment.

After carburizing, the rollers are taken from the containers and quenched after being reheated toapproximately 1500 degrees Fahrenheit. After the rollers are quenched, they are removed from r the quenching vessel and the shafts 4 inserted in ground away in the finishing operation. Accord- 1 ingly, the elimination or practical elimination of distortion is desired.

place. These shafts are then electrically spot welded completely around their circumference, as

The carburizing containers are preferably of such dimension that approximately 4 inches of carburizing compound cover the ends of the roller assemblies, which are vertically disposed,'and approximately 2% to 3 inches of carburizing compound surround the surface of the rollers. In addition, the inner chamber of each of the rollers is packed with carburizing compound; the entire space being filled. This minimizes the tendency of the roller to warp in the process of carburizing and hardening.

In View of the nature of the service to be encountered by the rollers, it is necessary to obtain a fairly deep carburized case of uniform depth on inner and outer surfaces of the roller body.

After the rollers have been disposed in the container and the container placed in the furnace, the temperature is slowly but uniformly raised. The rate of heating is controlled to avoid a large difierential in temperature between the furnace chamber and the rollers. In the lower brackets (i. e. 200 degrees Fahrenheit-250 degrees Fahrenheit) this is permissible; but after the charge and furnace approach the desired carburizing temperatures, this differential is reduced.

Applicants have found that a temperature of 1700 degrees Fahrenheit and 1725 degrees Fahrenheit for a period of about 16 hours produces a case depth of approximately of an inch. In this instance, with the carbon contents ranging from .95 to 1.00%, the hypereutectoid zone of case is rather extensive. The rollers are then cooled in the furnace to approximately 800 degrees Fahrenheit, after which the container is removed.

By allowing the rollers to cool down slowly from shown at H, to the hub plates 3.

After the shafts have been installed, the rollers are ground with any suitable abrasive medium to the desired degree of finish.

While we have shown and described certain specific embodiments of the present invention, it will be seen that we do not wish to be limited exactly thereto, since various modifications may be made without departing from the scope of the invention, as defined by the following claims.

We claim:

1. A conveyer roller for conveying metallic articles comprising a carburized and quenched tube of steel which, before carburizing and quenching, included approximately .08% to .35% carbon and 35% to .90% manganese and a metallic supporting element afiixed to each end of said carburized and quenched tube, the resultant surface and hardness of the tube being such as to substantially increase wear resistance of the tube, and to substantially eliminate scratching and marring of the article passing thereover.

2. A polished conveyer roller for conveying metallic articles comprising a carburized and quenched tube of steel which, before carburizing and quenching, included approximately .1'7% carbon and .46% manganese and a metallic supporting element afiixed to each end of said carburized and quenched tube, the resultant surface and hardness of the tube being such as to substantially increase Wear resistance of the tube, and to substantially eliminate scratching and marring of the article passing thereover.

LARRY D. DONBECK. ROBERT A. PETERSON. 

